minify CSS and JS with PHP in Wordpress server side

Question

I'm looking to add this to my framework to optimise it further. I don't want to use a plugin and I want the code to be as light weight as possible. This is the code I have so far. This works if I only call "style.css" but if I call the other files it doesn't minify the files. I'm getting the same with the js file I have. It removes the white space but it doesn't fully minify the file. Hope someone can help. Thanks

    <?php

$dev_master_root = dirname(dirname(dirname(dirname(dirname(__FILE__)))));
if ( file_exists( $dev_master_root.'/wp-load.php' ) ) {
    require_once( $dev_master_root.'/wp-load.php' );
} elseif ( file_exists( $dev_master_root.'/wp-config.php' ) ) {
    require_once( $dev_master_root.'/wp-config.php' );
}  

/* Add your CSS files to this array (THESE ARE ONLY EXAMPLES) */
$cssFiles = array(
  "../style.css",
  "global.css",
  "slicknav.css"
);

$buffer = "";
foreach ($cssFiles as $cssFile) {
  $buffer .= file_get_contents($cssFile);
}

// Remove comments
$buffer = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $buffer);

// Remove space after colons
$buffer = str_replace(': ', ':', $buffer);

// Remove whitespace
$buffer = str_replace(array("\r\n", "\r", "\n", "\t", '  ', '    ', '    '), '', $buffer);

// Enable GZip encoding.
ob_start("ob_gzhandler");

// Enable caching
header('Cache-Control: public');

// Expire in one day
header('Expires: ' . gmdate('D, d M Y H:i:s', time() + 86400) . ' GMT');

// Set the correct MIME type, because Apache won't set it for us
header("Content-type: text/css");

// Write everything out
echo($buffer);

?>

Section of output with the minify file exactly as above.

    body {
    color: #2d2e32;
}

h1 {
    font-size: 24px;
}

h2 {
    font-size: 21px;
}

h3 {
    font-size: 18px;
}

h4 {
    font-size: 16px;
}

h5 {
    font-size: 12px;
}

h6 {
    font-size: 11px;
}

h1, h2, h3, h4, h5, h6 {
    line-height: 1.618;
    margin-bottom: 20px;
}

p {
    font-family: 'Domine', serif;
    font-size: 12px;
}

#dev-master-main-container {}

#dev-master-header-container {
    background: #fff;
}

#dev-master-content-container {}

#dev-master-footer-container {
    background: #000026;
}

#dev-master-footer-content {}

@media screen and (max-width :1180px) {}

@media screen and (max-width :960px) {}

@media screen and (max-width :768px) {}

@media screen and (max-width :524px) {}

html {
    font-family: sans-serif;
    -webkit-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    height: 100%;
}

body {
    margin: 0;
    height: 100%;
}

article, aside, details, figcaption, figure, footer, header, main, menu,
nav, section, summary {
    display: block;
}

audio, canvas, progress, video {
    display: inline-block;
    vertical-align: baseline;
}

audio:not([controls]) {
    display: none;
    height: 0;
}

[hidden], template {
    display: none;
}

a {
    background-color: transparent;
}

a:active, a:hover {
    outline: 0;
}

abbr[title] {
    border-bottom: 1px dotted;
}

b, strong {
    font-weight: 700;
}

dfn {
    font-style: italic;
}

h1 {
    font-size: 2em;
    margin: .67em 0;
}

mark {
    background: #ff0;
    color: #000;
}

small {
    font-size: 80%;
}

sub, sup {
    font-size: 75%;
    line-height: 0;
    position: relative;
    vertical-align: baseline;
}

sup {
    top: -.5em;
}

This is the output when only style.css is called using the minify file. i.e when I remove "global.css" and "slicknav.css"

h1,h2,h3,h4,h5,h6 {}p {}#dev-master-main-container {}#dev-master-header-container {background:#fff;}#dev-master-content-container {}#dev-master-footer-container {background:#000026;}#dev-master-footer-content {}@media screen and (max-width :1180px) {}@media screen and (max-width :960px) {}@media screen and (max-width :768px) {}@media screen and (max-width :524px) {}

So in the code above, this is only style.css but you can see all comments etc are being stripped. It's super light weight because all the foundation styles are called from global.css

I have just noticed the spaces in this code which I would also like to remove. I thought the string above would have done that...?

Let me know if you need any more info. Thanks again

Answer 1

Are you referencing the file locations correctly in the array?

Also with the current code you have it is not going to perform a full minification because that involves switching out variable names for shorter ones e.g (someVariableName would become a)